Taguchi method approach on catalytic degradation of polyethylene and polypropylene into gasoline

Plastics have become indispensable materials in the world. They are non-biodegradable polymers of mostly containing carbon, hydrogen. Due to their non-biodegradability and low life, HDPE, LDPE, and PP contribute significantly to the problem of Municipal Waste Management. Thermal and Catalytic converting of these materials into the valuable liquids like gasoline and diesel would be a promising method of waste management. Current paper focuses on catalytic cracking of the mixed polyethylene and Polypropylene in the presence of silica alumina catalyst in a semi batch reactor operating isothermally at ambient pressure with a statistical approach. The parameters affecting degradation of polymer mixture studied in this paper include the temperature (410–450 °C), catalyst (10–50 wt%), and feed composition (1–5). The statistical Taguchi experimental design method has been used to optimize the reaction condition in degradation process in order to maximize the gasoline production. The liquid and gas products were analyzed by GC/FID to find out their composition. Using more catalyst leads the reaction to produce more aromatic components. The result of experiments discussed in this work compared with empirical data shows that the use of Taguchi as a DOE method has an appropriate approach to the optimum condition. Arrhenius law as a kinetic model at optimum reaction condition has been developed and the activation energy determined. The model gives a suitable representation of the experimental results.